There is no clear answer as to which is better. One is coaxial and the other is a right angle valve. The coaxial can open faster because the piston has a shorter travel distance and less air to dump. A typical right angle piston might have to travel 4 or 5 times farther than a coaxial piston to allow the same airflow.

In a coaxial, however, the air must make a 180 degree turn, as opposed to the 90 degree turn in the other design. So supah style valves probably have greater airflow.

Any piston valve is difficult to make. If I were going to use one I'd probably buy a Supah. At least I'd be assured the thing would work.

The valves I use are like the coaxial piston in your first link, but instead of a piston they have a thin diaphragm. It's easy to make (well.. with a little practice it's easy... the first one can be a pain), cheap, and performance is excellent (Cv = 21 for 1.5" , Cv = 43 for 2"). Here's a link:

i have already made a free floating piston. it was made out of a shampoo bottle filled with hotglue and wrpped in tape. it worked great. i dont see why everyone seems to make fancy pistons with O-rings.

air does have to turn 180 in the supah valve.

the only advantage i can see of the supah valve is that it allows you to have a much bigger chamber due to not have the barrel running through it. but id image its actuates slower and its harder to make.

it is definitely harder to construct a supah-type-piston valve, yet it is believed to have a higher cv, correct me if im wrong, but i agree they are pretty equal and they both have there advantages and disagvantages, but for its ease of construction i would say thats one big advantage for the "free floating" piston valve